Due to the low ambient temperatures in which some aircraft are expected to operate, aircraft can suffer from ice accretion in fuel lines. Water is an unavoidable contaminant in fuel and if the fuel temperature drops to around 0 degrees Celsius or below then ice formation can occur. If this ice formation is allowed to reach certain components such as engine fuel filters then blockage of the filter can exceptionally occur. In extreme cases this could cause engine failure (Ref: AAIB Special Bulletin S1/2008).